Biodiesel is a mixture of Fatty Acid Methyl Esters (FAME) formed by transesterification of vegetable oils and / or animal fats with methanol, in the presence of a catalyst. Biodiesel can be produced chemically and enzymatically. The aim of this work was to synthesize biodiesel in an enzymatically catalyzed transesterification reaction and to evaluate the energy efficiency of the process. For synthesis is used fresh edible sunflower oil, methanol and Amano lipase originating from Burkholderia cepacia at activity loads of 250 and 750 U/g of reaction mixture, whereas were used different concentrations and pH values of phosphate (200 mmol / L, pH 7 and 8) and universal Britton – Robinson's buffer (40 and 200 mmol/L, pH 10). Reactions were performed for 24 hours, and biodiesel samples were taken after 1, 2, 3, 6, 12, and 24 hours. The proportion of FAME was determined by gas chromatography. Optimal conditions for the implementation of enzymatic synthesis of biodiesel (content of fatty acid methyl esters in crude biodiesel greater than 99%) with B. cepacia lipase during the first hour of synthesis are 50 °C, molar ratio of oil and methanol 1: 3.4, lipase activity load of 250 U/g of the reaction mixture with 200 mmol/L Britton-Robinson buffer pH 10. Enzyme-catalyzed transesterification proved to be energy efficient (EROEI > 1), with an energy output to energy input ratio of 1.16.